Tinnitus is common, and some individuals with tinnitus display high levels of distress. Cognitive behavioural therapy (CBT) is effective in reducing tinnitus distress, but is rarely available. CBT-based self-help, with or without guidance, has yielded positive results in other problem areas, and one initial randomized controlled trial (RCT) has shown promising results for tinnitus.This thesis is based on four studies;Study I showed that Internet-based self-help treatment with e-mail guidance alleviated tinnitus distress among consecutive patients and was rated as credible as traditional treatments. Active participation in treatment predicted outcome.Study II, an RCT, showed that an extended and more interactive version of the Internet-based self-help treatment with e-mail therapist support appeared to be equally effective as a group treatment. In study III, another RCT, a self-help book with weekly telephone support was superior to a wait-list control group. No strong evidence for the importance of telephone contact on outcome was found. In both study II and III, the positive outcome remained after one year and self-help approaches appeared more therapist time-effective compared to group treatment. Also, the received treatment-dose for patients in guided self-help was not lower than in the group treatment.Study IV found that the ‘Stages of Change’, from the transtheoretical model, are probably not the right theoretical framework to use with tinnitus patients. Predictors of outcome were found, but they were not in line with the theory behind the Stages of Change. The predictors were better understood when conceptualized as coping, showing that helplessness and less coping before treatment correlated with better outcome.In sum, guided cognitive behavioural self-help can decrease tinnitus distress. It appears to be therapist time-effective and shows effects comparable to or slightly below traditional CBT for tinnitus. Effects remain one year after treatment and generalize to a routine clinical setting.